Conventionally, it is proposed to operate a heater at the time of requesting to heat air having been supplied to a passenger compartment in which a fuel cell is installed after the completion of the warming-up of the fuel cell (for example, see Japanese Unexamined Patent Application Publication No. 2010-267471). In addition to this, there are various proposals of a combination of a coolant circulation passage of the fuel cell and an air-conditioning circuit that shares the coolant (for example, see Japanese Unexamined Patent Application Publication Nos. 2013-168281, 2013-177101, and 2008-130470).
However, in Japanese Unexamined Patent Application Publication No. 2010-267471, even when the fuel cell system is placed, for example, in a low temperature environment, the heater is operated after heating is requested. Therefore, it might take time to warm the coolant flowing in the air conditioning circuit, which might cause low responsiveness to a user's request. Furthermore, the power consumption might be increased by using the heater. These disadvantages might also occur even in the proposals of Japanese Unexamined Patent Application Publication Nos. 2013-468281, 2013-177101, and 2008-130470.